Microwave oven



FIG. 1 is a perspective view of a microwave oven, showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a right elevational view thereof;

FIG. 7 is a left elevational view thereof. 

The ornamental design for a microwave oven, as shown. 